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News story: 8 August 2013: Alrode, Johannesburg, RSA

Exceptional Performance From Warman® SLR Pump

Weir Minerals Africa has obtained consistently
exceptional results after introducing a Warman® SLR medium duty
slurry pump on trial at Consol Industrial Minerals (CIM) in Cape
Town more than a year ago. After 2 000 hours of operation the pump
was opened for its first inspection, revealing that there had been
no visible on the impeller or sealing arrangement.

While the competitor pump required an impeller
change every 3 000 hours, the Weir Minerals Africa team confidently
predicts that the patented SLR pump will last as much as four times
longer – up to 12 000 hours — before replacement will be needed. At
the time of going to press, no wear parts on this pump have needed
replacing.

CIM, an established customer of Weir Minerals
Africa, has been in operation for more than 40 years, mining silica
sand primarily to supply the Consol Glass factory in Bellville. CIM
also produces special application silica sands for many other
external markets. The operation is located on a 96 hectare site in
the heart of Philippi which contains a natural silica deposit, and
mining currently takes place to a depth of 20 metres below ground
in a dredging operation. The silica sand is screened and washed,
then sized using a hydro-sizing process. Once dried, the sand is
packaged for bulk delivery. The CIM process plant produces about
200 000 tons of silica sand annually.

“When this customer started experiencing gland
sealing arrangement problems with an existing pump, we offered them
a trial replacement with one of our new technology SLR pumps to
improve both the sealing arrangement and the overall performance,”
Rui Gomes, product manager for slurry pumps at Weir Minerals
Africa, says. “The maintenance and short wear life of the existing
pump parts were also an ongoing problem. The existing unit was
leaking while in operation which, in turn, caused the shaft sleeves
to fail, resulting in regular packing change-outs.

“The Warman® 75 SLR pump has proved to be the
solution to these problems. This pump is fitted with an expeller
that seals the gland without any leakage while in operation and
does not require any external flushing water.

“The SLR pump’s very effective Hi-Seal® shaft
seal is a major improvement on what has been available up until now
and, from the outset, we saw an immediate improvement at the CIM
plant. Regular monitoring has proved that the pump is sealing
correctly and continues to do so.”

In addition to the patented Hi-Seal®
arrangement, Gomes attributes the excellent performance of this
pump to its hydraulic design. A single-piece rubber volute has been
adopted instead of two liner halves for alignment purposes. This
volute is moulded in Weir Minerals’ proprietary state-of-the-art
abrasion and corrosion resistant R55™ rubber. This rubber has
consistently shown very good resistance to shearing in test and
field installations, ultimately extending the lifespan of the wet
end parts for longer periods than those of conventional elastomer
products.

“Another feature that improves wear life is
that both the adjustable throat bush and back liner are fully
adjustable, keeping the impeller clearance at an optimal distance,”
he adds. “This is a feature on all our new pumps and it is really
paying dividends. Over time, the gap between the side liner and the
impeller opens up as a result of wear and by simply adjusting this
clearance regularly, plant operators can maintain pump efficiencies
at optimal levels throughout the life of the pump. The liners and
impeller are fully replaceable and the latest high performance
centrifugal shaft seal design is provided as standard.”

The SLR pump uses high capacity bearings which
allow it to operate with a much higher motor capacity if required,
as opposed to installing a larger sized pump. The shaft diameter
has also been increased to minimise deflection and lengthen the
life of the bearings.

“One of the most attractive features of this
particular pump is the sealing arrangement on the bearing
assemblies which prevents the ingress of foreign materials that
compromise bearing life,” Gomes comments. “This is a feature
that has been added in response to market requirements, making it
possible for plant operators to hose down the pump without any risk
of water causing the bearings to fail prematurely.”

Warman® SLR slurry pumps are fully
manufactured in South Africa at Weir Minerals Africa’s foundry and
rubber shop in Gauteng.

Rui Gomes, slurry product manager for Weir Minerals
Africa.

During R&D phase, the Warman SLR
undergoes rigorous testing at the local test bay facility.

The new Warman SLR slurry pump with a pump
liner manufactured with the new R55 material on display at the
Alrode facility.